1. Field
One or more exemplary embodiments relate to an optical modulator, and more particularly, to an optical modulator having pixelization patterns so as to obtain image modulation with high resolution.
2. Description of the Related Art
An optical-electric-optical (O-E-O) modulator, which receives optical information (images) to convert the optical information into electrical information, modulates the electrical information, and outputs the optical information (images), may have functions of converting wavelengths, amplifying light and performing modulation at a high speed, and thus, has been used as a core component in three-dimensional (3D) cameras, laser radars (LADARs), and infrared (IR) imaging.
The O-E-O modulator operates by a mechanism of receiving images having wavelengths of about 800 nm to 1700 nm, that is, an infrared ray (IR) band, generating electric currents using the photoelectric effect, amplifying or modulating the electric currents to a desired waveform such as a sine waveform, a ramp waveform, or a square waveform, supplying the electric currents to a light emitting device such as a light-emitting diode (LED) to output images having wavelengths of about 450 nm to 650 nm, that is, a visible ray band which has a high sensitivity with respect to an imaging device such as a charge-coupled device (CCD), in proportion to the received images.
An image intensifier, which uses a multi-channel plate (MCP) in an electron amplification, is a representative device that adopts the O-E-O modulator. However, the MCP is fabricated by forming holes, which have a diameter of a few μm, in a glass by as many as the number of pixels, and the MCP includes a vacuum package for the electron amplification. Therefore, fabrication costs are increased and the volume of the MCP is too large.
Therefore, semiconductor-based O-E-O modulators, which are small and massly produced, have been developed recently, and the semiconductor-based O-E-O modulators have been mainly realized on a GaAs substrate.